John D Curtis

US Patent:

4364501, Dec 21, 1982

Filed:

Dec 15, 1980

Appl. No.:

6/216195

Inventors:

John Curtis - Belmont CA

Assignee:

Instrumental Products - Redwood City CA

International Classification:

B26D 102

US Classification:

225 13

Abstract:

An assembly for dispensing tickets in strip form from a roll thereof registers a cutting blade with respect to drive openings in the strip of tickets, the drive openings occuring at the opposite ends of each ticket.

US Patent:

52046419, Apr 20, 1993

Filed:

Mar 11, 1992

Appl. No.:

7/849504

Inventors:

Slawomir J. Fiedziuszko - Palo Alto CA
John A. Curtis - Sunnyvale CA

Assignee:

Space Systems/Loral, Inc. - Palo Alto CA

International Classification:

H03B 518
H03B 714

US Classification:

331 96

Abstract:

A conducting plane resonator (10) is used to stabilize an oscillating means (12) typically operating at microwave frequencies. The conducting plane resonator (10) is in proximity to the oscillating means (12) and is magnetically coupled thereto. In a first implementation, the conducting plane resonator (10) is magnetically coupled to an input conductor (16) of the oscillating means (12). In a second implementation, the conducting plane resonator (10) is magnetically coupled to an output conductor (18), which is coupled to the oscillating means (12). In a third implementation, the conducting plane resonator (10) is magnetically coupled to both the input conductor (16) and the output conductor (18). The conducting plane resonator (10) preferably comprises a thin, substantially planar conducting plane and is dimensioned such that it is resonant at the desired operating frequency. The conducting plane resonator (10) is preferably fabricated of a superconductor material to achieve high-Q performance.

US Patent:

54847648, Jan 16, 1996

Filed:

Nov 13, 1992

Appl. No.:

7/975803

Inventors:

John A. Curtis - Sunnyvale CA

Assignee:

Space Systems/Loral, Inc. - Palo Alto CA

International Classification:

H01P 1201
H01B 1206

US Classification:

505210

Abstract:

A filter for an electromagnetic signal is formed of a set of planar resonators, preferably of superconductor material, interspersed among a set of electrically conductive sheets, outermost ones of the sheets serving as ground planes, and the inner ones of the sheets having irises for coupling electromagnetic power between the resonators. The resonators and the sheets have a planar shape, are parallel to each other, and are stacked one upon the other. Dielectric material insulates and serves to support the resonators and the sheets in their respective locations. There are at least two resonators in the set of resonators, and at least one inner sheet of the set of sheets. A first coupling element serves to couple an electromagnetic signal to a first resonator of filter to excite in the first resonator a first mode of electromagnetic vibration in a plane defined by the axis and a point of coupling of the first coupling element. Each of the resonators, in a preferred embodiment of the invention, is provided with a perturbation, such as a notch or a tab in a peripheral portion of the resonator, distant from the plane and from a coupling point for inducing a second mode of electromagnetic vibration perpendicular to the first mode, thereby to provide the function of a multiple pole filter with half the number of resonators.

US Patent:

51362686, Aug 4, 1992

Filed:

Apr 19, 1991

Appl. No.:

7/688038

Inventors:

Slawomir J. Fiedziuszko - Palo Alto CA
John A. Curtis - Sunnyvale CA

Assignee:

Space Systems/Loral, Inc. - Palo Alto CA

International Classification:

H01P 1203
H01P 708

US Classification:

333204

Abstract:

A dual mode microstrip resonator (1) usable in the design of microwave communication filters. The substantially square resonator (1) provides paths for a pair of orthogonal signals which are coupled together using a perturbation located in at least one corner of the resonator (1). The perturbation can be introduced by notching (3) the resonator (1) or by adding a metallic or dielectric stub (5) to the resonator (1).

US Patent:

52891399, Feb 22, 1994

Filed:

Nov 13, 1992

Appl. No.:

7/975781

Inventors:

Slawomir J. Fiedziuszko - Palo Alto CA
John A. Curtis - Sunnyvale CA

Assignee:

Space Systems/Loral - Palo Alto CA

International Classification:

H03B 518

US Classification:

331 56

Abstract:

A push-push microwave oscillator has two branch oscillators fabricated of a transistor and transmission line elements extending from terminals of the transistor, and a resonator which is fabricated of an annulus of superconductor material and serves to phase lock oscillations of the two branch oscillators. The superconductor material is a composite of a rare earth element and copper oxide such as yttrium-barium-copper oxide. A first transmission line in each of the branch oscillators extends past the resonator with a spacing to provide for electromagnetic coupling between the branch oscillator and the resonator. A second transmission line in each of the branch oscillators has a length equal to approximately one-quarter wavelength of the oscillation frequency to tune the branch oscillator to a common oscillation frequency. A third transmission line in each of the branch oscillators extends towards a junction point to form a summing unit for summing oscillations of the two branch oscillators to provide an output signal of the oscillator. The oscillator is constructed in stripline or microstrip form wherein components of the branch oscillators are coplanar with the resonator and are spaced apart from a ground plane by a dielectric layer of alumina or lanthanum aluminate.

US Patent:

51720841, Dec 15, 1992

Filed:

Dec 18, 1991

Appl. No.:

7/809868

Inventors:

Slawomir J. Fiedziuszko - Palo Alto CA
John A. Curtis - Sunnyvale CA

Assignee:

Space Systems/Loral, Inc. - Palo Alto CA

International Classification:

H01P 1203
H01P 708

US Classification:

333204

Abstract:

Planar dual mode filters (30) are formed by a conductive resonator (20) having circular symmetry and two pairs of symmetrically oriented planar conductive leads (22, 26 and 24, 28). The conductive leads (22, 26 and 24, 28) are aligned colinearly with two orthogonal diameters (32, 34, respectively) of the circular conductive resonator (20) and are electrically isolated from said resonator (20). A perturbation (38) located on an axis (36) oriented symmetrically with respect to the two pairs of conductive lead (22, 26 and 24, 28) couples electromagnetic modes which are injected into the resonator (20) by the planar conductive leads (22, 26 and 24, 28). Higher order filter circuits can be realized by combining multiple filters (30) of the present invention. The filters (30) are amenable to printed circuit (microstrip to stripline) fabrication using superconductors for the conductive elements.